To understand the link between vitamin D deficiency and dyslipidemia and cardiovascular disease, researchers conducted a large, cross-sectional study. However, it is still unclear why vitamin D supplementation did not provide clinically significant improvements to lipid concentrations.
“Epidemiologic studies suggest an inverse association between circulating levels of 25-hydroxyvitamin D (25[OH] D) and cardiovascular risk biomarkers, including an atherogenic lipid profile,” researchers wrote.
Although vitamin D deficiencies are common and effectively treated by supplementation, researchers said that the role as a modifier for CV risk has yet to be defined. Manish P. Ponda, MD, MS, from The Rockefeller University in New York, NY, and colleagues collected and analyzed over 4 million de-identified patient laboratory test results from Quest Diagnostics from September 2009 through February 2011. Quest Diagnostics investigators also participated in the study.
“This is relevant for practitioners as well as the general population, because of the increasing consumption of pharmacologic doses of vitamin D sold over-the-counter,” researchers wrote.
In the cross-sectional study population, researchers included 107,811 patient records to determine the link between 25(OH)D levels and lipids across clinically defined strata, in addition to a retrospective study of vitamin D patients to examine how 25(OH)D levels related to changes in lipid levels.
According to data, patients with desirable 25(OH)D levels (>30 ng/mL), compared with vitamin D deficient patients (<20 ng/mL), had lower mean total cholesterol (–1.9 mg/dL; 95% CI, –1.2 to –2.7), lower LDL cholesterol (–5.2 mg/dL; 95% CI, –4.5 to –5.8), higher HDL cholesterol (–4.8 mg/dL; 95% CI, –4.5-5) and lower triglycerides (–7.5 mg/dL; 95% CI, –6.2 to –8.7).
Moreover, retrospective cohort analysis results showed that raising vitamin D levels from <20 ng/mL to >30 ng/mL in 6,260 patients, compared with the remaining 2,332 patients, was associated with an increase in total cholesterol (P=.01) and HDL cholesterol (P=.02). However, there were no significant changes in LDL cholesterol (P=.06) or triglycerides (P=.97).
“These novel findings and approach provide a different type of evidence for clinical practice guidelines than existing association studies. Clinicians are still awaiting the results of large, randomized, placebo-controlled outcomes trials of vitamin D supplementation,” the researchers wrote.
It is for this reason researchers concluded that it remains unclear why vitamin D supplementation did not improve the lipid profile of patient data that were investigated.
Disclosure: Xiaohua Huang, Mouneer Odeh, and Harvey Kaufman, MD, are employees of and own stock in Quest Diagnostics.